Israel plans an invasion of Gaza

On items like this you never know how real the threat is. It would certainly be surprising if Israel wasn't working on plans to "retake" Gaza, but whether that means an attack like this will actually come to pass is another matter entirely.

ISRAEL’s new defence minister Ehud Barak is planning an attack on Gaza within weeks to crush the Hamas militants who have seized power there.....

The raid would be triggered by Hamas rocket attacks against Israel or a resumption of suicide bombings.

I would put this as another possibility of many. How is it that both the Israeli and US policy apparatus seem to be surprised by this? Isn't it their job to plan for contingencies?